Scrubbers are utilized in a variety of applications for the purpose of cleaning contaminated air to acceptable levels of corrosive, malodorous gases and/or particulate matter. Various applications require this type of complete air filtration solution. For example, such applications are required for airports, museums, electronic or pharmaceutical clean rooms, petrochemical and refining industries, indoor air applications as well as various other facilities. These and other industries all have specific needs related to a specific industries, but all require the ability to scrub contaminated air to acceptable levels.
Several types and methods of use for scrubbers have been used in the past. These systems may be classified to wet and dry scrubbing systems. Wet scrubbing systems that use a water or chemical spray to solvate and concentrate the contaminants in an air stream into a liquid stream for removal from the air stream. On the other hand, dry scrubbing systems use specially formulated solid adsorbents for the collection of gaseous contaminants. The solid adsorbents utilized include, for example, impregnated or non-impregnated activated carbons and potassium or sodium permanganate supported over activated alumina that can physically or chemically adsorb contaminants out of the air stream. The solid adsorbents may be loaded into a filtration section having one or more media beds. A stream of air is then passed through the one or more media beds to clean the air of certain gases and matter. After the solid adsorbents have been used in the scrubbing system for a period of time they will become loaded or spent. Such spent solid adsorbents are then replaced with fresh material to continue efficient and effective scrubbing operations.
Dry scrubbers operating in this fashion have typically utilized fixed bed volumes. The operating lifetime impacts the media replacement schedule and related media replacement costs and the amount of pressure drop impacts energy usage of the scrubbing system and associated energy costs. Dry scrubbing systems typically have fixed volume media beds within which the adsorbent media is loaded. As a result, in a typical fixed volume media bed design the energy usage is non-alterable over the lifetime of the scrubbing system and the media replacement schedule is also non-adjustable by a user over the lifetime of the scrubbing system.
It would be desirable to overcome these and other deficiencies by making the bed volume alterable, to provide for decreased pressure drop and also decrease the residence times and improve media capture efficiency.